The invention relates generally to digital computer data management systems, and more particularly to a system for controlling interfaces between a plurality of computers and a plurality of peripheral devices and communication circuits which may employ different communication disciplines.
The term "communication (or line) discipline" may be defined as a set of rules or criteria governing the transfer of data to or from a particular peripheral device. Exemplary factors distinguishing one discipline from another involve, for example, data format, control signal sequence synchronization, start and end of message sequences, message signal lengths, etc. Many different communication disciplines have evolved which are now well known to those skilled in the art. The following list comprises only a small portion of those disciplines which might be of interest in a typical on-line data management system:
______________________________________ (1) VIP Visual Image Projection Terminal (Honeywell) (2) DN355 Datanet 355 (Honeywell) (3) Baudot TTY ITA Number Two Teletypewriter (4) ASCII TTY ASCII Teletypewriter- Odd or Even Parity (5) BISYC Point-to-Point Binary Synchronous Communications ______________________________________
Due to a lack of standardization of the various communication disciplines, it is generally necessary for a system to include separate communication and input/output controllers to accommodate each different discipline to be handled by the system. In some data management applications, it is not unusual for a system to have to accommodate six or more types of major network disciplines plus a multitude of other disciplines for specialized terminals and peripheral devices. To aggravate the problem further, new disciplines are continually being developed which, in turn, require that new controllers be designed if an existing capability is to be expanded to accommodate the new discipline.
Systems for facilitating effective communication between multiple peripheral devices employing different communication disciplines and the main memory of a controlling computer are described in U.S. Pat. No. 4,075,691 to J. S. Davis et al and U.S. Pat. No. 4,079,452 to K. N. Larson et al.